EFFECTS OF ACOUSTIC STIMULI ON THE WAKING HUMAN BRAIN

Publisher Website
Google Scholar
Abstract
Acoustic stimuli cause electrical on- and off-effects in the waking human brain. There appeared to be no difference between [alpha] and non-[alpha] types of subjects. The on-effect was most prominent at the vertex. The first phase was negative. Its latency was about 30 to 40 msec. The total duration of the on-effect was approximately 0.3 sec. or less. The voltage measured from peak to trough ranged from just visible to 100 VV. Frequently there was an off-effect similar to the on-effect, but never as prominent. A checking of the a rhythm was sometimes the only visible response; "Anticipatory" on- and off-effects appeared when a regularly spaced sequence of tones was unexpectedly stopped or prolonged. If the "psychological set" remained unaltered in relation to the expt., but the physiological condition progressed from alertness to sleep, the on-effect would always become more predictable and more prominent.